Measuring the tenderness of meat

ABSTRACT

To test raw meat in order to determine how tender it will be upon cooking, meat bodies to be tested are first classified as to their fat content and probe tests are then made upon the meat portions in a particular class and the results of individual tests compared.

United States Patent Hansen *Sept. 5, 1972 [54] MEASURING THE TENDERNESSOF 3,123,997 3/1964 Cosuer ..73/81 MEAT OTHER PUBLICATIONS [72]Inventor: Leo J. Hansen, Clarendon Hills, 111.

Pearson, Ob ective and Sub ective Measurement for [73] Asslgnee: Armourand Company Chlcago, Meat Tenderness from Proceedings Meat TendemessSymposium 1963 N ti Th ti f h e f hi Szczesniak et al. Methods of MeatTexture Meas.

t t subsequent t J l 22 1983 from Advances in Food Research vol. 14 Junehas been disclaimed. 1966 PP 35 McBee et al. Influence ofMarbeling***Beef" Jour- [22] May nal of Animal Science vol. 26 1967 pp.701, 702 [21] Appl. No.1 35,147 Carpenter et al. Correlations***Marbeling***Tendemess Journal of Animal Science vol. 17 1958 p.Related US. Application Data 1 153 [63] Continuation-in-part of Ser. No.776,234, Nov. p Of Agriculture Form 11$ 106 15, 1968, Pat. No.3,593,572, which is a continuation-in-part of Ser. No. 705,722, Feb. 15,Exammer-lames Gill 1968 Attorney-Dawson, Tilton, Fallon & Lungmus [52]US. Cl. ..73/78 ABSTRACT [51] Int. Cl. ..G0ln 33/12 To test raw meat inorder to determine how tender it [58] Field of Search 73/78, 81, 84, 432will be upon Cooking meat bodies to be tested are first classified as totheir fat content and probe tests [56] References cued are then madeupon the meat portions in a particular UNITED STATES PATENTS class andthe results of individual tests compared 2,446,956 8/1948 Ross ..73/81 8Claims, 10 Drawing Figures l1l"MIMI-E IIIIIIDE IIIHIIIII illll J//////Ill\\\\\\\\\ PAIEZNTEDSEP 5 ma SHEET 1 BF 5 M T H V N I LEO J. HANSENPATENTEDSEP 5|912 SHEET 2 BF 5 INVENTORI LEO J. HANSEN BY= (kw (flagATT'Y slsesgsss PATENTEDSEP 51912 SHEET 3 0F 5 BATTERY CHARGER V0 LTA GE REGULATOR NETWORK MEMORY CIRCUIT DIFFERENCE AMPLIFIER TRANSDUCER amuseLEO J. HANSEN ATT'Y FIG? INVENTOR: LEO J. HANSEN ATT'Y PAWNIEEESEP 5:972

SHEET 5 [IF 5 INVEN TORI LEO J. HANSEN MEASURING THE TENDERNESS OF MEATRELATED CASES This application is a continuation-in-part of my copendingapplication Ser. No. 776,234, now US. Pat. No. 3,593,572 filed Nov. 15,l968, which, in turn, is a continuation-in-part of my copendingapplication Ser. No. 705,722 filed Feb. 15, 1968.

BACKGROUND AND SUMMARY The housewife has long been troubled by theproblem of determining tenderness in meat. Pressing a fork or fingerinto the meat gives a vague idea of softness, but there is no standardor measure which assures her that the meat when cooked will have adefinite degree of tenderness. The meat packer has long sought to solvethe problem. There have been chemical tests, biochemical tests, andphysical tests, but none have given a reliable measure of the tendernessof the raw meat which will carry over into the cooked product.

The structure of meat itself explains the difficulty. The connectivetissues, which constitute about ten percent or more of the total proteinof the meat and which forms a network throughout the meat body, are verydifferent from the contractile protein or muscle fiber which mayconstitute as much as 90 percent of the meat protein. On cooking, thecontractile protein readily coagulates, while the connective tissue tosome extent breaks down into gelatin. How can one predict the tendernessof the cooked product which may be free of some of the connective tissuewhen the test is made upon raw meat in which the connective tissue is anever-present factor in determining the resistance to probing, etc? Amongthe physical tests, persons skilled in the art have used blunt heads orsurfaces to press the meat, but here the connective tissue disappointsthe measurements because the tissue draws together substantial meatareas. Pointed probes have been used in testing thin cuts of meat whichare not suspended or supported except for a base support, but here thetest fails because the meat of such cuts moves laterally duringpenetration by the probe and an accurate record of the resistance of themeat is not obtained.

In Technical Bulletin No. 1231 of Agricultural Marketing Service, UnitedStates Department of Agriculture (July 1961), penetrometer tests weremade in which a spade-pointed needle carrying a 200 gram weight wasallowed to penetrate thin meat cuts for seconds in a direction parallelto the grain of the meat and the results recorded, and it was found thatthere was no relationship between the penetrometer tests and tenderness,the conclusion being as follows:

Penetrometer Measurements. This determination,

which should indicate ease of muscle fiber separation, was made only onsamples from the last 2 years of the study (102 carcasses). The resultswere not consistent for the 2 years, and the combined averages do notindicate any appreciable relationships between carcass grade or weightand penetrometer readings on raw ribeye.

I have discovered that when a needle or group of needles having pointedends are pressed into the meat to a predetermined depth, the force usedin moving the needle to such depth being measured and compared with aknown standard, an extremely accurate, consistent and reproducible testof tenderness is achieved, and this is confirmed uniformly by subjectivetenderness panels who evaluate the cooked meat. I have also discoveredthat consistent and reproducible results can be obtained even when theprobe is pressed under constant pressure for a selected time into meatand the distance of penetration measured if the meat is suspended orsupported on its sides during such penetration.

A problem is presented in applying the probe process to meat bodiesgenerally because of the varying fat content of such bodies and thevarying resistance responses to probe penetration due to the presence ofthe fat. At least one worker in the field has directed that fat beavoided in making resistance tests on meat. I have discovered that meatbodies can be accurately probetested regardless of their intramuscularfat content by first classifying meat bodies or portions according totheir fat content and then making the probe tests upon meat portions ina particular class and comparing the results with standards which havebeen arrived at for this particular class. Thus with a class of meatbodies having generally about the same or similar fat content, probetests can be made readily to accurately predict the tenderness of themeat bodies when cooked.

When the above tests are made upon a section of the longissimus dorsimuscle within the carcass or carcass half, it is found that theprediction in general indicates the degree of tenderness for the musclemeat of the entire carcass.

DRAWlNGS In the accompanying drawings,

FIG. 1 is a side view in elevation of a simple instrument which may beemployed in the practice of the process for measuring the penetration ofprobes or needles to a predetermined level in the meat;

FIG. 2, a somewhat similar instrument provided with means for anchoringit upon a forequarter of the carcass to bring the needles or probes intoalignment with the ribeye of the carcass:

FIG. 3, a view similar to FIG. 1 but showing the housing of thetransducer broken away to show the strain gauges and diaphragm, etc.;

FIG. 4, a schematic block diagram of an electrical system which may beemployed with the structures shown in FIGS. 2 and 3;

FIG. 5 is a side view in elevation of a suspended beef carcass halfshowing the carcass cut to expose the ribeye;

FIG. 6, a broken plan view on an enlarged scale of a section of the halfcarcass taken parallel with the rib and an inset view of greatlyenlarged muscle fibers which extend within the ribeye muscles andangularly with respect to the backbone;

FIG. 7, another view showing the enlarged muscle fibers illustrated inFIG. 6, the view being taken parallel with the severed backbone at line7-7 as indicated in FIG. 6;

FIG. 8, another view of the muscle structure and the angularly-extendingmuscle fibers illustrated in FIG. 6, the view being taken, as indicated,at line 88 of FIG.

FIG. 9, a support for holding or suspending a piece of meat for probetesting in accordance with my invention;

and FIG. 10, a broken side view in elevation of the device shown in FIG.9 with a piece of meat held thereby.

DETAILED DESCRIPTION The process and apparatus which will be describedherein are applicable to all types of meat, as, for example, the fleshof cattle, hogs, sheep, poultry, fish, and other edible meat. For thepurpose of simplicity and clarity, however, the invention will bedescribed herein in connection with beef carcasses and meat.

In the structure shown in FIG. 1, l designates a frame member in theshape of an inverted U and having at its bottom inwardly turned stops11. The frame 10 may be provided with a fixed handle 12. Depending fromthe frame 10 is a support 13 to which is secured a transducer 14. Fromthe transducer 14 extends a pressure member 15 secured to a plate 16from which a number of needles 17 depend. These may be in the form of ablock of needles which are spaced apart so as to engage simultaneouslyan area of muscle to determine the average tenderness of the areaengaged. An electrical conduit 18 extends from the transducer to arecording gauge instrument 19 for indicating the force in terms ofpounds employed in penetrating the meat to a depth provided by the stops11. the strain gauge or transducer 14 may be of any suitable type, as,for example, the type shown in US. Pat. No. 2,472,047 or US. Pat. NO.3,130,382.

Any suitable measuring device may be employed for measuring the force ofpenetration of the meat and this may include a spring gauge and recorderand similar instruments. For example, a spring gauge with a lazy hand"indicator may be employed, the lazy hand being moved during penetrationof the meat to record the maximum force and remaining in position Afterpenetration by the probe so that the operator can record the reading.The hand may then be moved manually back to the starting position. Thereare definite advantages, however, in employing electronic means for theextreme accuracy required during extensive and long usage, and in thisoperation there is induced in a transducer an opposing force equal tothe force of penetration of the meat by the probe while generating anelectrical signal representative of the opposing force. The signal, ifdesired, may be directly proportional to the induced opposing force, andthe electrical signal may be in the form of visual indicia.

In the structure shown in FIG. 2, 20 indicates a bearing plate which ispressed against the outer surface of a carcass half 21, the cut exposingthe ribeye portion 22 of the longissimus dorsi. The beef carcass issevered between the 12th and 13th ribs to expose the ribeye portion onthe forequarter, while the Ioineye portion of the longissimus dorsiextends through the hindquarter.

The bearing plate 20 is preferably provided with inwardly extendingprongs 23 and with a fixed handle 24. Rods 25 extend through bosses 26fixed to the plate 20 and are secured at their rear ends by handle 27.Compression springs 28 extend between the bosses 26 and the handle 27.The rods 25 are secured at their inner ends to a clamp plate 29 whichextends upwardly at an inclination and is fixed at its top to the anchormember 30. The plate 30 is provided with spaced cars 31 through which apivot pin 32 extends to support the handle 33 between the ears 31. Thehandle 33 may be provided with a tubular grip 34 through which extendsthe electrical conduit 35 leading to an indicator gauge (not shown) butwhich may be similar to gauge 19, as shown in FIG. 1.

The handle 33 is provided with an arcuate slot 36 in which is mounted aroller 37 pinned to the upper end of stem 38. The stem 38 extendsdownwardly through the guide 39 carried by platform 40 fixed at itsinner end to the clamp plate 29.

The stem 38 extends into a transducer 41 which may be similar totransducer 14 of FIG. 1, and a pressure stem 42 extends from the lowerend of the transducer 41 to the plate 43 carrying the pointed probes orneedles 44. The needles 44 are arranged in a block and may be arrangedso as to traverse in a uniform way the cross section of the ribeye 22.

In order to limit the depth to which the needles descend, there isprovided a stop 45 near the upper end of stem 38 and which will engagethe guide boss 39 to limit downward movement of the needles 44.

If desired, the clamp plate 29 may be provided with inwardly extendingpins 46 for engagement with the carcass portion 21 so that the testingapparatus will be firmly anchored to the carcass portion to produceuniform movement of the needles 44 with respect to the ribeye or otherportion of the meat being tested.

In the practice of the invention, the carcass or meat portion to thetested is brought to a predetermined temperature for the testingoperation, such as, for example, in the range of 30 to 50 F. andpreferably in the range of 32 to 40 F. Test measurements may be made 12or 24 hours after slaughter or after a week or more following slaughter.

By way of specific example, after a carcass has been chilled to about 32to 40 F., the lower half '2], as shown in FIG 2, may be secured asindicated in the drawing and the handle 33 lowered to move the needles44 perpendicularly, the stop 45 limiting the downward movement so thatthe penetration is for two inches or any other selected depth. The forcein pounds is registered on the gauge instrument, such as gauge 19, andthe maximum force indicated on the gauge is recorded. The recorded forcein pounds is then compared with a standard which has been previouslydetermined and the deviation from the standard gives the degree oftenderness of the meat. In determining the standard, meat of a knowntenderness, as determined, for example, by subjective tenderness panels,is tested under similar temperature conditions so that it provides aguide for the tests.

When electrical means are employed for measuring the resistance of themeat to the probes, I prefer to employ an instrument such as is shownbest in FIG. 3 in a circuit as shown in FIG 4. Referring to FIG. 3,strain gauges 14a are mounted on a flexible diaphragm 14b. The centralportion of the diaphragm 14b is directly coupled to the center of abottom 14c by means of a shaft 14d, and the upward movement of thediaphragm 14b is limited by means of an adjustable bolt 14. While twostrain gauges are shown in F IG. 3, it is preferred to use foursemiconductor strain gauges which are mounted along a common diameter ofthe diaphragm 16.

Two of the four gauges are preferably arranged to measure compressiveforces and the other two transducers are arranged to measure tensileforces.

For purposes of understanding the present invention, there is set out afunctional block diagram of the entire circuit so that the function ofeach circuit element is shown in cooperation with the other elements. Asshown best in FIG. 4, the transducer bridge is schematically designatedby the block 47 and it generally operates an output signal along lines48, the instantaneous difference in potential between the lines 48 beingrepresentative of the instantaneous penetration resistive forceencountered by the probe needles 17 during insertion.

The signal lines 48 are fed to the input of a difference amplifierstoring which is modified to amplify only those signals representativeof the insertion forces and to discriminate against signals of oppositepolarity. The output of the difference amplifier 49 is coupled to amemory circuit 50 which includes a capacitor for storing charge. Thecapacitor is fed by a circuit which permits current to flow onlyunidirectionally so that if the insertion of the probe is unsteady and,for example, slows down for a short time so that the output signal fromthe transducer bridge 47 begins to diminish, the memory capacitor is cutoff or disconnected from the output of the difference amplifier 49during this period. Thus, if the force signal diminishes, charge is notdrawn from the capacitor so that the accumulated charge on the memorycapacitor in the memory circuit 50 is representative of the peak of thepenetration resistive force encountered. The output of the memorycircuit 50 is fed to a read-out or recorder device 51 for displaying orrecording the measurement.

A storage battery and charger circuit 52 is coupled through a voltageregulating network 53 to energize the transducer bridge 47 so that theentire system is portable and may be set up at different locations. Thebattery may be recharged, and the voltage regulating network 53 insuresthe proper voltage level being fed to the resistive transducer bridge 47so that operation is substantially independent not only of the chargestate of the battery but also of the ambient temperature in which thesystem is being used. The battery and charger circuit 52 also contain ascaling circuit so that the charge state of the supply battery may beread by means of the read-out device 51, which preferably is a meter,and properly scaled to indicate such charge state.

Excellent results can be obtained when the probe or probes areintroduced into the ribeye or other muscles at an angle to the grain ofthe meat (direction of muscle fiber orientation). The muscle fibers 54in the longissimus dorsi, as illustrated best in FIGS. 6, 7 and 8, runat an angle to the backbone. For example, as shown in FIG 6, there is anangle of 34 between the muscle fibers and a line parallel to thebackbone 55 of the carcass. The backbone 55 and a rib 56 are shown bestin FIG. 6 of the drawings. In another view taken from line 7-7 as shownin FIG. 6, the muscle fibers 54 extend at an angle of 36 from a lineparallel with the backbone 55. IN FIG. 8, the muscle fibers 54 are shownto extend at an angle of from a line parallel with the backbone 55. Thethree figures show the orientation of the muscle fibers which make upstructure within the relatively large longissimus dorsi extending almostthe full length of the backbone of the animal. The structure of thislarge muscle is attached by connective tissue to the backbone at manypoints along its length. While it might be expected that the musclefibers extend longitudinally of the large muscle, they actually do notbut instead extend at an angle with the length of the muscle and areoriented with respect to the backbone.

When the probes 17 are introduced into the face of the exposed ribeyelying generally in a plane transverse to the backbone, as shown in FIG.6, and in a direction perpendicular to the face of the cut, it is foundthat the probes pass through the ribeye muscle at an angle of about 45to the grain of the meat. By passing the probe into the meat at an angleto the muscle fibers, rather than in a direction parallel with themuscle fibers, a more accurate measure of the tenderness of the meatbody is obtained. The angle between the prober and the fibers ispreferably in the range of about 10 to and best results are obtainedwhen the angle between the probe and the muscle fibers is in theneighborhood of 45.

When the tests are made upon the ribeye muscle or similar muscles withthe muscles supported within the carcass, as shown in FIGS 5 and 6, veryaccurate measurements are obtained because the muscle is suspended andsecurely held by the bone structure of the carcass. The muscle isstrongly attached to proximate bones and other tissues and ligaments byconnective tissues so that the muscle is held securely during thetesting operation. On the other hand, if thin cuts are made of themuscle and the cuts placed upon a supporting surface, the measurementbecomes less effective because the muscle body moves away from the probeas the probe is pressed into the cut. In testing a meat body, such as,for example, a muscle cut indicated by the numeral 57, as shown in FIG.10, I prefer to employ supporting and suspension means such as are shownby FIGS. 9 and 10. For example, a block 58 is provided with a guide 59extending through the slot 60 of angle member 61. The angle member 61 issecured to a clamping block 62 adjustably movable toward a stationaryblock 63, the two blocks being provided with stainless steel needles orretainer elements 64. This structure supports the meat body on severalsides, and in addition suspends the meat so that the meat cut or body issupported firmly during penetration of the meat by the testing probes17.

With the meat cut or body suspended as illustrated in FIG. 10, effectivetenderness tests can be made even when a constant pressure, as by meansof a weight, is employed for pressing the probes into the meat through apredetermined period of time and the extent of penetration measured. Thesuspension of the meat body enables such a test to be accuratelyutilized. However, I find that more satisfactory results are obtainedwhen the probes are introduced into the supported or suspended meat cutto a predetermined depth, as, for example, to a depth of about 2 inches.

Another means for supporting the meat is illustrated in FIG. 2 in whichthe forequarter is shown with the severed longissimus dorsi muscleexposed for the penetration thereof by the pointed probes or needles 44,and the plate 20 together with the rods 25, clamp plate 29, andcompression springs 28 provide a retainer for the meat being tested.Such a clamp retainer means may be used for muscle piece after it hasbeen extracted from the carcass so as to hold the muscle portion in itsinitial position or form during the penetrating test operation. Anysuitable retainer means may be provided for holding the meat cut beingtested against substantial distortion during the period when the pointedprobes are being pressed into the meat.

When the carcass is suspended, as shown in FIG. 5, and the carcass bodyis severed to expose the longissimus dorsi muscle, an ideal arrangementfor making the test is provided because the backbone and ribs of thecarcass body together with the strong connective tissue suspend andsupport the muscle firmly during the test, and additional clamping meansare not necessary.

In the manual apparatus illustrated in FIGS. 1 and 3, the U-shapedmember 10 is provided with inwardly turned stops or feet 11, and whenthe probes are being pressed into the meat the feet 11 serve asindicators that the probes are being pressed evenly on all sides intothe meat. In the pressing operation, the operator makes sure that thefeet 11 contact the top surface of the meat at the same time.

In the testing of beef and other meat cuts where there is a varyingintramuscular fat content. I find it important first to classify themeat according to the intramuscular fat content and then make the testsupon the meat portions in a particular class and then compare theresults with standards which have been arrived at for this particularclass. The reason for this is that when the tests are made, as I preferto make them at a temperature in the range of about 32 to F., the fatbecomes relatively hard and this has an effect upon the resistancereading. It is important therefore to establish standards for each ofthe classes into which the meat portions fall by reason of the amount ofintramuscular fat which they contain. By way of example, the meat bodymay be classified according to U.S. Department of Agriculturespecifications into U.S. prime, U.S choice, U.S. good, etc. In general,the prime classification contains more intramuscular fat than choice,and choice more than good, etc., so that these grades may be utilized asa classification according to intramuscular fat. Also, I can utilize anyother classification which recognizes the difference in intramuscularfat.

Thus, in a preferred operation, a beef carcass may be suspended and thecarcass sawed vertically through the backbone to provide two carcasshalves, and the suspended half then severed between the 12th and 13thribs. In actual operation, the operator locates the top of the 13th ribat approximately the center of the side, inserts the knife, and makes acut along the rib toward the flank, then reverses the knife and cuts tothe backbone where he meets a cut made by the operator sawing thebackbone. The knife cut meets the sawed cut evenly so that there is nooffset. The fore part of the carcass then drops down somewhat to openthe carcass providing a V-shaped opening indicated by the numeral 80 inFIG. 5, thus to expose the ribeye. An examination at this time enables askilled person to determine the class of the carcass. If at this timethe marbling or intramuscular fat content of the ribeye of a particularcarcass indicates that the carcass falls under the class of 1.1.8.choice, for example, the operator, after testing the ribeye asheretofore described with the probes, compares the deviation of therecorded force from a known standard relating to the US. choice class,and from this an accurate prediction of the tenderness of the ribeye cutis obtained. Further, since the longissimus dorsi is an accurateindicator of the tenderness of the entire carcass, the measurement isapplicable to the other cuts of meat in the carcass.

My methods can be practiced without reference to any predeterminedstandard simply by taking a number of carcasses and arbitrarily or byany preselected rule, dividing them into different classes according totheir intramuscular fat content, the relatively high intramuscular fatcontent carcasses being put in one class and the relatively lowintramuscular fat content carcasses in another class. Then the carcassportions of each class are tested and each reading is compared with theother readings in the same class. From this comparison the relativetenderness of each carcass portion is readily obtained. In one sense,this practice utilizes the readings obtained on the other carcasses ofthe same class as a standard against which the readings as to eachcarcass may be compared. For example, each reading within the class maybe compared to the average of the other readings in this same class todetermine if the meat in this carcass is relatively more tender orrelatively less tender than the average of the lot. After a large numberof readings have been taken for any prescribed class, a general standardis obtained against which the readings of any carcass of similarintramuscular fat content can be compared. The results so obtained arefound to be more reliable than if the tests are made without the initialclassification as to intramuscular fat content.

The precise relationship between the intramuscular fat content to theamount of resistance to the penetration of a probe into the muscle isnot now known, but I have found that, in general, the greater the amountof this type of fat content in the muscle, the greater will be theresistance to probe penetration, other conditions remaining the same,and in particular, I find that any amount of fat would affect theresistance rending to a greater extent at lower temperatures, down totemperatures approaching freezing. For these reasons I find itimportant, in order to get best results, to work in as narrow a range oftemperatures and as narrow a range of intramuscular fat content as ispractical. Preferably, the carcasses to be tested should first beclassified as to intramuscular fat content and then the carcass portionsof each such class checked to see that their temperatures fali within apreselected range before the probes are inserted and readings taken.From the observation above expressed that a higher temperature of theintramuscular fat affects the resistance reading to a lesser degree, itmight be supposed that one should prefer the higher temperature of meatin the conduct of the tenderness test, but this is not actually thecase. I find that there is actually greater accuracy and dependabilityof the test results when the temperature is kept low, such as in therange of about 32 to 36 F.

Why the methods herein described will accurately predict how tender themeat will be on cooking when, in effect, the cooked meat is quitedifferent from the raw meat, the connective tissue to some extentbecoming gelatin in the cooked meat and the contractile protein ormuscle fibers becoming coagulated, I am unable to state with any degreeof certainty. It may be that the network of connective tissue in the rawmeat has an irregular gathering effect during penetration causingerratic and high forces to register before the full depth is reached,while a constant depth of penetration with the pointed probe or needleminimizes or averages out the connective tissue factor so that the netmeasurement is substantially that of the muscle fiber or contractileprotein and residual undegraded connective tissue which togetherdetermine the tenderness of the cooked meat. In any event, themeasurement of the force of penetrating the raw meat to a fixed depthwith the pointed probe, as described above, does accurately predict thetenderness of the cooked meat.

As above stated, I prefer to test a cross section of the longissimusdorsi muscle because this not only is a valuable meat portion but I findit is surprisingly indicative of the character of the other muscles inthe carcass, and thus by determining the tenderness of the ribeye orloineye, an accurate prediction of the tenderness of all muscle portionsof the carcass is furnished.

I am also unable to say with certainty why it is possible, as herein setforth, to obtain more accurate results when the pointed probes areinserted at an angle with the direction of the grain of the meat, ormore particularly, lengthwise of the longissimus dorsi muscle, and at anangle with the fibers of the muscle. It may be that tenderness is afunction of both the resistance to crosspenetration or rupturing of thefibers and the resistance of the fibers to separation one from another.By passing the probes at an angle to the fibers, both of these factorsare taken into account in producing the resistance reading.

While my invention may be practiced using but a single probe or needlefor penetrating the meat, I prefer to use a plurality of probes becausein this way the resistance reading obtained measures the total of theresistance to all the probes which, when related to the readings ofother tests, amounts to the equivalent of a comparison of the averageresistance to the probes and in this way, error is minimized.

Further, I prefer to arrange the configuration and spacing of the probesor needles so as to conform with the outline of the muscle being testedand to penetrate representative portions of such muscle. In the specificprobe device herein described, there are 10 probes designated by thecharacter 17 and these are arranged in rows of five in one direction andtwo in the other direction each equidistant to in other to make apattern roughly conforming to the longissimus dorsi muscle. This enablesthe operator to confine the penetration to the muscle and to penetrateit at equally spaced points over its cross-sectional area. This featureis important as may be seen especially by reference to FIGS. 2 and 6where there are definite fatty areas 81 located peripherally of themuscle 22. Thus, the probe conforms generally to the length and breadthof the muscle and makes it easy to avoid the situation where one or moreof the probes would penetrate the fatty area 81 instead of the muscleitself and thus to avoid error in the reading obtained.

In the foregoing description of my methods I have referred toclassifying the carcass according to intramuscular fat content,separating the classes and conducting tests for comparison within eachclass. This should not be taken in a sense which would require physicalseparation and spacing of the carcasses, although this actual physicalseparation may be done. In packinghouse operations there may be 10, 100or 1,000 carcasses in a large cooler where the carcasses are broughtdown to the final chilled temperature, such as 32 to 36 F. with thesecarcasses hanging close to each other on rails within the cooler.Although it is possible to classify the carcasses as to intramuscularfat content and separate them physically with different classes ondifferent rails, this is not essential. The carcass may be left in theirsame physical locations as they come into the cooler and the operator,in conducting the tenderness tests, may approach each carcass down theline as it is suspended on the rail, making tests and making atabulation as he goes along, giving in the tabulation an identificationfor each carcass half or other carcass portion together with its classas to intramuscular fat content, giving its temperature or noting if itis in the preselected temperature range, and noting the reading obtainedfrom the dial 19 of the testing device for this particular carcass orcarcass portion. This practice gives the necessary classification andseparates the classes so that resistance readings may be readilycompared within each class. From this tabulation can be obtained theidentification of each carcass portion within each class as tointramuscular fat content and the identification of each carcass portionwithin each range of tenderness which may have been previously set as tofat content in each class. Such information enables characterization bythe packer of each portion according to tenderness, which has neverbefore been possible.

I have found that the resistance readings taken of the longissimus dorsimuscle in the left half of the carcass compare very closely to thosetaken in the muscle in the right half of the same animal carcass so itis not necessary that tests be made on both halves of the same carcassand the reading made on the one half of a carcass may be taken asapplicable to the other half as well. Accordingly, when the operatormoves through the cooler making tests, he may simply skip the lefthalves (or the right halves) and pass on to the next carcass half.

The freezing and thawing of the meat is found to produce negligiblechanges in the tenderness quality of the meat; hence after thetenderness tests are made, the meat may be frozen and held for weeks ormonths. The meat may be thawed and cooked and will then be found toreflect the tenderness qualities indicated by the test on the raw meatbefore freezing.

The temperatures at which the tests may be made are not critical. Thetests may be made immediately after slaughter, but this is not preferredbecause of the softness of the fat and for other reasons, and duringrigor mortis the muscles contract and it is not a desirable time to makethe tests. Preferably the tests are made after rigor mortis and aftercooling the carcass. The carcass should not be cooled to the extent thatice crystallization occurs, and preferably the temperature should not beraised to the point where bacteria causes deterioration of the meat,such as slime-forming bacteria. While great latitude is permitted withrespect to temperatures, I prefer to bring the meat after slaughter andafter the period of rigor mortis to a temperature in the range of 32-40and to make the tests at a temperature within this range. Such a rangeallows ready correlation with taste panel tests and the propercalibration of the measuring instruments.

Specific examples illustrative of the process may be set out as follows:

EXAMPLE I Penetration resistance measurements of three U.S. choice beefcarcasses were made 24 hours after slaughter when the internaltemperature of the ribeye has been brought down to 32-40 F. The ribeyewas exposed in the customary manner by partially severing the carcassbetween the 12th and 13th ribs. The multiple needle probe, as shown inFIG. 1, was then forced in to a depth of exactly 2 inches goingperpendicularly into the face of the exposed ribeye.

For the test work, the short loins were taken, after breaking thecarcasses into wholesale cuts, and held at 3240 F. for one week afterslaughter. Two-inch thick slices were then cut off and roasted in a 350oven to 150 F. internal temperature.

Samples of cylindrical shape, one inch in diameter, were cut and thebrowned surfaces cut off before presentation to panel members. Samplesidentified only by code designation unknown to the judges were presentedto a panel of eight skilled and experienced judges. The judges wereasked to evaluate the tenderness on a hedonic scale which ranged from 8(extremely tender) down to l (extremely tough). Panel scores were takenby averaging the eight responses.

The results were as follows:

Needle Sensory Penetration Panel Sample No. Resistance Score 1 1 1.3lbs. 7.1 2 15.7 lbs. 6.0 3 21.5 lbs. 5.1

EXAMPLE II Tests were made in the manner described in Example I ofsamples of beef carcasses one week after slaughter during which time theinternal temperature of the carcass was held in the range of 32-40 F.and panel tests were made at the time. The results were comparable tothose described in Example I, thus demonstrating that the needlepenetration to a constant level tests accurately predict tenderness eventhough the penetration tests were made on meat at a longer time afterslaughter.

EXAMPLE III A number of beef carcasses suspended, as shown in FIG. 5 ofthe drawings, were tested by the manual instrument shown in FIGS 1 and 3of the drawings. The carcasses with the ribeye exposed, as shown inFIGS. 5 and 6, were classified, in one class the U.S. prime and U.S.choice being grouped together, and in the other class were placedcarcasses having less marbling or intramuscular fat. The probe assemblywas applied so that the needles were located in the approximate centerof the ribeye muscle and thus did not contact any sinew, cartilage,bone, or cover fat, the probes extending into the ribeye muscle at anangle of about 45 to the inclination of the muscle fibers. With asteady, smooth pressure, the needles were pressed downwardly until thestop indicators or feet I 1 just touched the surface of the ribeye. Thereadings were then made from the dial. After each reading, the dial armwas brought back to zero.

In the first grade, which included U.S. prime and U.S. choice, allresistance readings up to 15 pounds were stamped with the code letter P,indicating high tenderness. For the resistance reading between 15.1 upto 18, the letter A was stamped upon the carcass to indicate theacceptable but lower degree of tenderness.

Similar stamps of the code letters were placed upon the chuck, rib,short loin, loin end, and round cuts of the carcass.

In testing the other grades below U.S. prime and U.S. choice, resistancereadings up to 13 received the stamp P for the carcass, while carcassesin which the resistance readings were from 13.1 to 15 received the stampA, and similar stamping was made upon the five places on each side,namely, the chuck, the rib, the short loin, the loin end, and the roundportions of the carcass.

EXAMPLE IV Tests similar to those described in Example [11 were madeupon suspended hog carcasses and the resistance determinations made, thelongissimus dorsi muscle being tested by prongs fitting the area of thesevered muscle.

EXAMPLE V Resistance readings by prongs such as described in Example Imay be utilized by pressing the same into the breast of poultry todetermine the tenderness of the breast muscle. Similarly, tests may bemade upon the dark meat of the poultry.

A raw fish carcass may be treated as described above in the case ofpoultry and the tenderness of the meat muscle determined by theresistance readings.

In the case of both poultry and fish, the bone structure is preferablyused for supporting the meat in firm position during the testingoperation.

As set out above, the temperatures at which the probe tests are made arenot critical and can vary from room temperature (about F.) down to 32 F.Within such a temperature range, however, and where there is asubstantial fat content, I prefer to hold the class of meat bodies beingtested at fairly close temperature ranges of about 8-10 and preferably46. Further, since bacteria developed rapidly at temperatures above 50F., I prefer to maintain the meat bodies classified for the test at atemperature in the range of 3250 and preferably in the range of about3340 F. Excellent results have been obtained at a temperature in therange of 363 8 F. Meat after slaughter contains bacteria which aresingle celled organisms which multiply by each cell dividing into two,spoilage occurring after about 20 division. I prefer therefore to keepthe temperatures below 50 F. and preferably in the range of about 32 or33-40 F. To prevent material change in the meat, I prefer to maintainthe temperature in the range of 3242 F. after slaughter and until theprobe tests are made.

While in the foregoing specification I have set forth specific apparatusand steps in considerable detail for the purpose of illustratingembodiments of the invention, it will be understood that such detailsmay be varied widely by those skilled in the art without departing fromthe spirit of my invention.

1 claim:

1. [n a process for testing raw meat bodies of varying fat contents todetermine how tender they will be after cooking, the steps ofclassifying said meat bodies according to their fat content to obtain atleast a first class having a higher range of fat content and a secondclass having a lower range of fat content, probe resistance testing meatbodies in said first class to ascertain their relative tenderness anddetermine a general resistance standard for tenderness in said firstclass, probe resistance testing meat bodies in said second class oflower fat content similarly to determine a general resistance standardfor tenderness in said second body class, and pressing a probe into ameat body in one of said two classes and comparing the resistance of themeat to the movement of the probe against the resistance standard fortenderness determined for that class.

2. The process of claim 1 in which said bodies are maintained at atemperature of about 32-40 F. during said probe testing.

3. The process of claim 1 in which said bodies are maintained within atemperature range not exceeding 8 in an overall temperature range ofabout 3275 F.

4. The process of claim 1 in which said probe is pressed to apredetermined depth.

5. In a process for testing raw meat bodies of varying fat contents todetermine how tender they will be upon cooking, the steps of classifyingsaid meat bodies according to their fat content to obtain at least afirst class having a higher range of fat content and a second classhaving a lower range of fat content, pressing a pointed probe into aplurality of meat bodies in one of said classes and measuring andcomparing the resistance of the meat to the movement of the probe insaid plurality of bodies to determine a resistance standard fortenderness in said class, similarly pressing a pointed probe into aplurality of meat bodies in said other class and determining aresistance standard therefor, and pressing a pointed probe into a meatbody in one of said classes and comparing the resistance of the meat tothe movement of the probe against the resistance standard determined forthat class.

6. The process of claim 5 in which the maximum resistance to themovement of the probe is the resistance measured and compared.

7. The The process of claim 5 in which the meat bodies during testingare maintained in a temperature range of about 32-40 F.

8. The process of claim 5 in which the resistance standards fortenderness in said classes are proven by taste panel tests.

1. In a process for testing raw meat bodies of varying fat contents todetermine how tender they will be after cooking, the steps ofclassifying said meat bodies according to their fat content to obtain atleast a first class having a higher range of fat content and a secondclass having a lower range of fat content, probe resistance testing meatbodies in said first class to ascertain their relative tenderness anddetermine a general resistance standard for tenderness in said firstclass, probe resistance testing meat bodies in said second class oflower fat content similarly to determine a general resistance standardfor tenderness in said second body class, and pressing a probe into ameat body in one of said two classes and comparing the resistance of themeat to the movement of the probe against the resistance standard fortenderness determined for that class.
 2. The process of claim 1 in whichsaid bodies are maintained at a temperature of about 32*-40* F. duringsaid probe testing.
 3. The process of claim 1 in which said bodies aremaintained within a temperature range not exceeding 8* in an overalltemperature range of about 32*-75* F.
 4. The process of claim 1 in whichsaid probe is pressed to a predetermined depth.
 5. In a process fortesting raw meat bodies of varying fat contents to determine how tenderthey will be upon cooking, the steps of classifying said meat bodiesaccording to their fat content to obtain at least a first class having ahigher range of fat content and a second class having a lower range offat content, pressing a pointed probe into a plurality of meat bodies inone of said classes and measuring and comparing the resistance of themeat to the movement of the probe in said plurality of bodies todetermine a resistance standard for tenderness in said class, similarlypressing a pointed proBe into a plurality of meat bodies in said otherclass and determining a resistance standard therefor, and pressing apointed probe into a meat body in one of said classes and comparing theresistance of the meat to the movement of the probe against theresistance standard determined for that class.
 6. The process of claim 5in which the maximum resistance to the movement of the probe is theresistance measured and compared.
 7. The The process of claim 5 in whichthe meat bodies during testing are maintained in a temperature range ofabout 32*-40* F.
 8. The process of claim 5 in which the resistancestandards for tenderness in said classes are proven by taste paneltests.